The field of the invention is automatic nailing machines and more particularly the invention relates to machines for fabricating wooden pallets.
Automatic nailing machines for fabrication of pallets have been in widespread use for many years. One such machine is disclosed in U.S. Pat. No. 2,856,606 and further refinements of such machines are disclosed in U.S. Pat. No. 3,591,067. The machines disclosed in the above two patents are highly complex, somewhat simpler devices have also been devised, one of such being shown in U.S. Pat. No. 1,949,108. The purpose of such machines is to decrease the amount of labor required to fabricate wooden pallets and with continued increases in labor costs, interest in such machines continues. The machines of the prior art suffer from several shortcomings. Machines such as those shown in U.S. Pat. No. 3,591,067 are highly complex, very expensive and are relatively difficult to repair and maintain. Machines such as that shown in U.S. Pat. No. 3,207,403 utilize a mechanical nail driving linkage and in the event the machine becomes jammed severe damage can result.
For speed of production, it is advantageous to drive a plurality of nails at one time. For instance, for a pallet having five deck boards using 3 nails per board it would be desirable to drive 15 nails with one stroke of the machine. Attempts to achieve this result have led to the complex machinery such as shown in U.s. Pat. No. 3,591,067. Prior attempts to simplify the machinery have led to inoperative devices or devices with unsatisfactory service life.